Train control system



' TRAIN CONTROL'SYSTEM Original Filed N' v. 10. 1926 2 Sheets-Sheet 1 Q5 Q g h wventoz v flrhz LZ/lz'llz'amaarz aawwwm Oct. 20, 1931. A. G. WILLIAMSON 2 TRAIN CONTROL SYSTEM.

Original Filed Nov.- 10, 1926 2 Sheets-Sheer 2 351;; 11 Sum/14% Patented Oct. 20, 1931 I UNITED STA amen e. wrmimnson, or CARNEGIE, rnnnsrnvnma nssrenon, BYivInsNE Assmm MEN'FS, J THE UNION SWITCH & SIGNAL TRAIN CONTROL SYSTEM Originni application filed November '10, 1926, Serial-\No. 147,403,

' Y Y June 21,1929. Serial No.. 372,567.

This invention relates to train control systems, the train controlling means being traincarried signals, and/or retarding or stopping devices, and has for its main object and tea- Y tune to suitably correlate trackway and j train equipment in "a simple and effective 'This application is a division of application I Ser. No. 147,403, filed November 10, "192.. v w

In the accompanying drawings the inVen-I tion is disclosed by way {of illustration, but I not limitation, .inavconcrete and preferred form in which: r m Fig. 1 .is a diagrammatic view of a typical trackway equipment that maybe used inconnection with the invention; Fig. 2 is a diagrammatic ferred form of train-carried equipment;

VIFigs. "3 vand 3a are diagrammatic views of .a characteristic curve ofan electrontube .sho-W' the mannerin which said, characteristicEcurive can be used in carrying out' view of a prey the invention;

.F-rg. 4lis ta diagram illustrating the varia-. tions of the itrackway current; and

Rigs. z4aand 4b are diagrams illustrating the eflect'oi the Variations offFig. 4 on the an ,pla'te :current oi? the train-carried electron tube under tdi'fl'enent operating conditions.

' QE indicates a train-carried electron tube, detcctonhavinga v,platellPl, a gridG and a... .;fi1amentiF,,..said'tube11aving associated there? .lilament circuit having a current source. In this invention it is proposed to eil'ec't the control of the etrainby'varymg the average,

value of theacurrentiiow in the platefilament b circuit to do 'this by controlling the po tentiail-o f thegrid with respectto the filament jointly by two factors, viz: current flow 'in' v the gnid-filament circuit .in-responseto currentifiow in the traiiic rails, and other means such as afbattery, that constantly tend to establish a predetermined potential notwithstanding changes "intraific conditions. The invention further contemplates the employqmen't wot direct-current relay 'means that are responsive to changesln the average Value of current "flowingin the plate-"filament'cirfilament circuit.

Divided and this application filed cuit to thereby assume one condition when the gnd, potentlal is the result of the action of both of the above-mentioned factors and to assume a second condition when thegrid filament circuit ceases to be effectively influenced bytrack current.

stance, ,also a pick-up circuit and consists here of coil 1 in an inductive relation to the The" g-rid-filament circuit is, in this'inv I V c mma-or "swrssvnnn, rnnnsyn 'wima, nconronn'rron or PENNSYLVANLA quency of a trackway'current by means of tuning condenser 142, 'constitutesone-of the factors that controls the'potentialof the grid wi'threspec't -to the filament. The other factor thatcontrols this potential is battery 140 which is suitably connected to the gridvariable 7 resistance that may be employed in connection with battery 140. The plate-filament circuit is provided with a suitable cur- 141 is a potentiometer or i rent source, here indicatedby battery 83,

and responsive to the influence ofthe average value of current flowing in said plate-filament'circuit are suitable direct-current relay -means. Such relay means may take any of thejform's knowninthe art as disclosed for; instance in Letters 1 Patent No. 1,791,779 of February 10, 1931 and application Ser. No.

147,403 but it is preferred to employia directcurrent polarized relay as 24 which assumes one condition whenthe' grid potential is the :35 with a grid filament circuit and also a plate-1;. iresult of the action of both of-therbeforementioned factors andgto' assumea second relayassumes another-condition."- Relay 24 may also 'have i-a neutral armature 28. Relay 2 4 is biased,f'in any ofthe ways'known in the art as 1S fully described and disclosed .in Letters'Patent No. 1,7 91,779 of February a "10, 1931 and application Ser. No. 147,403, .to'

assume one condition when'direct current of an intermediate value, s'ay a-direct current Specifically,relay 24 I condition whenvariations of potential, dueto I I I of an average value ofObO, is flowing in the coil of the relay, and to assume a second condition when the current flow is either increased or decreased invalue with respect to said intermediate value; Inthecase here illustrated, relay 24 is biased so that plarized armature 80 will assume the right-' hand position, or the position shownin the Fig. 2, when the direct current flowing in the coils of the relay is of an intermediate value and of the proper polarity and will assume the left-hand position, or the posi-' tion opposite to that shown in Fig. 2, when 5 the direct current is either increased or decreased in value with respect to said intermediate value, notwithstanding that the polarity of the current remains the'same. Neutral armature 28 of relay 24 will remain lifted as shown in Fig. 2 at all values of the current except at a very low value, that is, a value much less than the intermediate value. As will be seen, armatures 28 and 30 control a circuit through traflic controlling means 33 which inay operate signals and/or brake application devices in a manner well understood. In the present instance, relay 24 is made subject to the in- I fiuence of variations in the average value of the current in the plate-filament circuit by being included directly in said circuit.

An instance of symmetrical variations produced by a suitable trackway current is in- I dicated in the diagram. Fig. 4 and as will be understood, similar variations are thereby induced in the grid-filament circuit which in turn produce similar symmetrical variations in the potential of the grid, In employing the electron tube in the manner disclosed, advantage is taken of the fact that the. plate current grid-voltage characteristic graph of an electron tube does not show a straight 1 line but a pronounced curve at its upper and lower ends as shown in Figs. 3 and 3a. By

7 means of a train-carried source of power such as batterylO, it is possible to so adjust the potential of the grid with respect to the filament. that, when no voltage is induced in pick-up coil 1, the operating point of tube Ewill be at point-N at the upper bend, or f at point N at the lower bend of the char acteristic curveofFigs. 3 and 3a. If'the operating point selected is point N at the upper bend (Fig. 3a) then when no voltage is induced in the pick-up coil the grid potential is represented by and thecurrent in the plate circuit will be represented by I.

' 'VVlien-an alternatingcurrent is induced in the piclcup coil byjthe current flowing in the trafiic rails, andth s alternating voltage is impressed between the grid and filament it a will produce, during every cycle, approximately equal and 'oppositevariations of potential of the grid with withrespect to the filament,represented by +6 and e, from the potentialderived from battery 140. ,Plotposition of polarized armature ting these variations of potential +6 and e on the curve of Fig. 8a, it is seen that he resultant variations 2' and 6 of the plate current are unequal due to the bend of the characteristic curve and since the decrease occasioned by the rail current therefore produo-es asyinmetri al current impulses or variations of the current in the plate-filament circuit that'result in a change in the average value of said current as illustrated by Fig 460. Therefore. if I assume that the full or original value of the current supplied by the battery 83 to the plate-filament circuit to be 1.00, then theasymmetrical variations i and 6 results in an intermediate average value of, let us say, 0.60. W'ith direct-current p0larized relay 24- biased in'the manner previously described, the polarized armature responds to this change in the average value of the current of the plate-filament circuit;

by swinging to the right-hand position as shown in'Fig. 2. In other words, the alternating rail current. having symmetricalvariations, or oscillations, induces in the pick-up coil on the train a current having similar;

variations that create similar symmetrical variations of potential of the grid, These symmetrical variations of grid potential, due to the potential established by battery 14:0,

manifest themselves by creating asymmetri= cal impulses or variations of plate-filament circuit current with the result that theaverage value of said current is changed. Relay 24- is responsive to this change in the average value of the current" of the plate-filament circuit and thereby directs a change in the 30 so that it willoccupy the position shown in Fig. 2. Conversely, absence of the symmetrical variations of the rail current will permit a cur rent of the value of 1.0 to flow in theplatefilament circuit and armature 30 will thereforeswing to the left in Fig. 2.

If the operating point N (Fig. 3). at the lower bend of the curve is selected, then the.

induced variations in pick-up coil 1 would produce a large increase and asmalld-ecreasc in the value of the current of the plate-filament circuit. In such case the original current supplied by battery 83 to the plate-filamentcircuit, that is, when there is no induced current in the pick-up coil andthe potential of the grid is that derived solelyfrom battery 14:0, will have a lowvalue. This low value is not suflicient to energize relayQfl: to

a :zigaaaaaz I overcdme' the biasing on polarized armature: 230i andcthereforeasaidr armature L30:islheld :iin

Patheletthand position. When the induced .-eurrent in pick-up coil 1 creates the increase I at each positivehalf cycleao't the induced currenttandthe F'decrease v at each negative halt? cycle in the current .of the plate-filament cireuitpthe :result 51's that :the -average value of said current is increased. This action, vvhere the symmetricali-variations .otithe in-l duced 1 current, result in :an increase in the average value of thecurrent ofth'epl-ate-fila- 'fment circuit, is illustrated in Fig. "4b. Let

wus assume that the original value of the "cur- .-rent in the iplate-filament'circuit is 70:20 and e that, asthe. .resu'ltofithevariations of grid potentialcaused by the induced current, the

7 :average value 'iproduc'ed is '0'. '60,=i'then'withj hand position. 7 y y :The :means for supplying current to the the directscurrent polarized relaybiased in EthBP manner previously 1 described, polarized armatureBO will respond ltoithis change in the average value-by swinging toxthe right rails-mayvarywidely andithe"hereinafter de- .:scribed system will serve as an exemplification ithereof. A =itrafl"1c track indicated by I 1railsi'55 and 56 is provided, and this track is divided into blo.cks,:'suoh asblocksA, B and =C,':as by'insula'tions 3, and' on thistra'fii'c track- I, traflic normally moves in but one direction,

1 that-direction beingiindicated inFig. l by end ot the Tblock, fand ted ibyga battery conw "nested across the rails at zthe outgoing end an arrow. Each :block is provided With the common track circuit consisting of a; track relay COllIlCtBdfiCIOSSthG rails at the ingoing of the block. il akingbloek B as an illustration,track relayl48 :is connected'to rails =an-d 56'at the-:ingoing end and track battery 155 is connected tothe rails at the outgoing mend of the block, A second track circuit, which also preferably; includesf the 'trafiic rails, is :provided for each :block. 7 This sec-. 45;

0nd track circuit :supplies a suitable current :such as an interrupted or a simple alternat- 111g currentto the rails;

I This current has symmetrical variat ons or oscillations, as illustrated iinFig. t, and this alternating-eurrent cooperates with train-carried apparatus ,in the manner previously pointed out. This second circuit! for a block is' controlled by the track relay for the block in'adv ance, and

-fic. conditions. Specifically, generator '51.

asthe' circuit closed only whensaid track relay is energized, the alternating 1 current is Supplied-to the railsonly under proceed trafsupplies'alternating current to line wires'52 5and 53 andtaking thecase of block B, transformer-.101 supplies "current from the line {wires toth'ecircuit that teedsthe rails. One

:side. of secondaryv 11 15v of transformer 101 is :connected to rail, 56*by wire 1 46, arniatu'reli'? of track relay 148 ofrblockC inadvance, conztact point 149 and wire i150, Therother side current.

is to choke back therfi owof alternating current through battery 155, and resistance 158 :current from secondary 145 when therails .eof'th'e blockareshunted'by a Whenever block Cris -unoecupied, relay"148 will close the circuit from secondary 145' to the. rails of block Bin the} rear, and a train entering suohblock B will'have its train cars, 'rie'cla-pparatus controlled by the alternating 7 current flowingin-the traflic rails; Such a a train-entering block B alsodeenergizes track :rela'y' 148 and fthis will openthe-alternating current eircuit fori'ablook in the rear of block B. If under these circumstances a train should enter block A, itstrain-carried apparatus would be'uninfiuenced by an alter f hating current; Likewise, should a train;

enter block B behind the first-mentioned trai n, then the first train 'Wlll have shunted the alternating current so that saidsecond train in block B will receive no alternating Should: axtrain equipped with theappa-ratus of Fig. 2- enter block B of 1, traveling inthe direction indicated by the arrow, and

block C in advance, as Well asblock B, be 1111- occupied by any other train, then "alternating current supplied by transformer 101 flows in the rails of block 'B toiinduce aicurrent in coil 1 on the train. This :inducedcurrent -'having oscillations similar 'to the alternating rail current causes positive and negative swings of the potential of gridG- With respect to the'original potentialderived from battery j 140, and as previously pointed out these swingsof potential, altho symmetrical, efiect through asymmetrical impulses, a change in the average value ofwthecu'rrentkin the 'plate-' filament circuit byfeither redueing it from a high :value to'an intermediate value as in the ease whereythe points-N is selected, or by increasing it :from alow value to the intermediate value, as in the case Where point N is selected. This change'in the value of the current in-the plateffilament circuit causes the polarized "armature to swing to the righthand position, andjas shown in Fig. 2 this closes the circuit to brake controlling and sign aling' device 33-to th ereby'holdthe brakes inoperative and to on the-train.

displayaproce'ed signal But'itblock C is occupied and bloclr B P unoccupied as the trainenters block B, then the flow of the alternating current-from transformer 101' to the rails of blockB is :cut {0a at contact 149 of track relay 1480f "block G; No current will thenbe induced in pick-up 'coil 'of the train entering block I "so i B, with the result that gridG of'tubeE has its potential with respect to the filament controlled only by battery 140, and the current in, the plate-filament circuit assumes its original value, which will be the high value if a point N is selected, and which will be the low value if point N is selected. Polarizedvare mature therefore swings to the left-hand position in response to the change in'the value of the current in the plate-filament circuit from the intermediate value back to the high or to the low value as the case may be, and by swinging to the left-hand position, opens Again, if block a B is already occupied by a train when a sec- 0nd train entersthe block at the ingoing end,- it is evident that the alternating current supplied by transformer 101 to the rails of block B will be shunted away from the second train by the wheels and axles of the first train, and

that there will be no current induced in the pick-up coil of the second train. Consequently, polarized armature 80 of the second train will assume the left-hand position in response to the absence of the alternating rail current.

I claim;

1. A continuously acting train control system including: traffic rails arranged in blocks, a train, a train-carried electron tube having a plate, a grid and'afilament, a traincarried plate-filament circuit having a current source that charges said circuit with current of a given average value, direct-current relay means responsive to the influence of the change in the average value of current flowing in the plate-filament circuit, that is produced by current impulses, created in said current, the influence of which is asymmetrical with respect to the original average value of said; current, means associated with "the electron tube to create said asymmetrical current impulses in response to symmetrical variations in the potential of the grid with respect to the filament, and a trackway current source that supplies to said rails, under proceed trafiic conditions, a current that by its influence produces symmetrical variations in the potential of the grid.

2. A continuously acting train control sys tem including: trafflc rails arranged in blocks, a train, a train-carried electron tube having a plate, a grid and a filament, a train carried plate-filament circuit having a cur- I rent source that charges said circuit with current of a-Vgiven average value, direct-cur- 'rent relay means responsive'to theinfluence of change in the average value of current flowing 1n the plate-filament c1rcu1t, that 1s produced by current impulses, created in sald current, the influence of whichis asymmetrical with respect to the original average value of "said current, means associated withthe electo establish a predetermined potential ofthe grid notwithstanding changes in traflic conditions; and a trackway current source that supplies to said rails, under proceed traffic conditions, a current that by its influence produces symmetrical variations of potential in the trainmarried grid-filament circuit.

3. A continuously acting train control system including: trafiic rails arranged in blocks, a train, a train-carried electron tube carried plate-filament circuit having a current source that charges said circuit with current of a given average value, a directcurrent polarized relay responsive to the inhaving a plate, a grid and a filament, a train fluence of the change in the averag l of current flowing in the plate-filament circuit, that is produced by current impulses, created in said current, the influence of which is asymmetrical with respect to the original average value of said current, means asso ciated with the electron tube to create said asymmetrical current impulses in response to symmetrical variations in the potential of the grid with respect to the filament, and a trackway current source that supplies to said rails, under proceed traffic conditions, a current that by its influence produces symmetrical variations in the potential of the grid.

- i. A continuously acting train control system including: traflic rails arranged in blocks, a train, a train-carried electron tube having a plate, a grid and a filament, a traincarried plate-filament circuit having a current source that charges said circuit with current'of a given average value, a direct current polarized relay responsive to the influence of the change in the average value of current flowing in the plate-filament circuit, that is produced by current impulses, created in said current, the influence of which is asymmetrical with respect to the original average value of said current, means associated with the electron tube to create said asymmetrical current impulses in response to symmetrical variations in the potential of the grid with respect to the filament consist ing of (1) a train-carried grid-filament circuit continuously responsive to the influence tential are absent from the grid-filament cir; cuit. I 1

9. A continuously acting train control system including traffic rails arranged in blocks, a train, a train-carried electron tube having a plate, agrid and a filament, a traincarriedplate-filament circuit having a currentsource that charges said circuit withcur rentjofa given average value, direct-current relay ,means responsive to the influence of the change in the average value of current flowing in the plate-filament circuit, that is produced by current impulses; created in said current, the influence of which is asymmetrical with respect to the original average value of said current, means to create said asymmetrical current impulses in response to symmetrical variations in the potential of the, grid with respect to the filament vincludmg: v(1) 3a train-carriedgrid-filament circuit continuously responsive to the influence of symmetrical variations of the current in the rails to thereby continuously reflect traflic conditions and (2) a power source connected to the grid-filament circuit, said power source constantly tending to'establish a predeterimined potential of the grid notwithstanding changes in tratfic conditions; and a trackway currentsource that supplies to said rails, 0 under'proceed traffic conditions, a current that-by its influence produces symmetrical variations ofpotentialin the train-carried grid-filament circuit.'*

, r 7 10. A continuously acting train-control sys- F tem including; traflic rails arranged in blocks, a train, a train-carried electron tube having aplate, a grid and a filament, a tra n-carried late-filament 'circuit'havi'ng a current source" .that;charges said circuit with current of a 4 given average value, a direct-current polarizedr'elay responsive to the influence of the change in the average value of current'flowing inkthe plate-filament circuit, that is-pro- ,duced by current impulses, created in said" current, the influence of which 1s asymmetniionsand (2) a power source connected to the grid-filament circuit, said powersource constantly tending to establish a predeters mined potential of the grid nothwiihstanding changes in trafiic conditions; and a" fio tra'ckway current source that supplies to said rails, under proceed traffic conditions, a current that byits influence produces symmetrh cal'va'riationsof potential in the train-carried grid-filament circuit. 7 i r 65 "11. A continuously acting train control when variations of potential igsaaei :system including: traflicrails blocks, a trackway current source that supplies to said rails, under proceed trafiic conditions, .a current that by its influence produces symmetrical variations of potential in a train-carried grid-filament circuit, a train; a train-carried electron tube having a plate,

a grid" and a filament, the potential of the grid being controlled jointlyby two factors including the following means: (1) a traincarried grid-filament circuit continuously responsive to the influence of the current in therails to thereby continuously reflect traf- I fic conditions'thereof and (2) a power source connected to the grid-filament circuit, said power source constantly tending to establish a predetermined potential of the grid notwithstanding changes in traflic conditions; a train-carried plate-filament circuit, a current source that charges said circuit with current of agiven value, the average value of the current flowing insaid plate-filament circuit being determined by the joint control' of said two factors, and direct-current relay means responsive to a change in the average value of the current flowing in the plate-filament circuit to assume one condition when the grid potential is the result of the action of both factors and to assume a second condition when variations of potenltial'are absent from the grid-filament circuit.

12. A continuously acting train control{.

system including: trafiic rails arranged in blocks, a trackway current source that supplies to said rails, under proceed traflic con ditions, acurrent that'by its influence pro duces symmetrical variations of potential in a train-carried grid-filament circuit, a train,

a train-carried electron tubehaving a plate, a gridand a filament, the potential of the gridbeing controlled jointly by two factors. including the following means: (1) a train-. carried grid-filament circuit continuously re-.

spo'nsive to the influence of the current in llbrthe rails .to thereby continuously reflect traf- I fic conditions thereof and (2) a power source connected tothe grid-filament circuit, said power source constantly tending to establish a predetermined potential of the gridnotwithstanding changes in traific conditions; a train-carried plate-filament circuit, a current source that charges said circuit with current of a given value, the average value of the'current flowing in said plate-filament circuit'being determined by the joint control of said-two, factors, and a direct-current polarized relay responsive toa change in the average-value of the current flowing in the platesfilament circuit and having an arma- 1 ture that assumes one position when the grid" potential'is the resultof the action ofv both 7 factors and that assumes a second position the grid-filament circuit.

are absent from V 13c imam v 1 continuously acting control system including: trafiic rails arranged in blocks,- a traokway current-sourcethat sup-' plies to-said rails,under proceed trafiic con-,

ditions, a current that by its influence produces symmetrical variations of. potential in a train-carried grid-filament circuit, a train, a train-carried electron tube having a plate, a grid and a filament, the potential of the grid being controlled jointly by two factors including the following means: a train power source constantly tending to establish a predetermined potentialof thegridnotwithstanding changes in traffic conditions;

a train-carried plate-filament circuit, a current source that charges said circuit with current of a given value, the average value of the current flowing in said plate-filament circuit being determined by the joint con-, I I

junction with the power source connected to trol of said two factors, a. direct-current .polarized relay responsive to a change in the average value of the current flowing in the plate-filament circuit, and an armature associated with said polarized relay that moves in one direction when vthe grid potential is the result of the action ofboth factors and that moves in the other direction when variations of potential are absent from the grid-filament circuit. V

14:. A continuously acting. train control system including: traflic rai'ls arranged in blocks,ra'trackway current source-that-sup= plies to said rails, under proceed 'trafliccon ditions, a'current thatby its influence produces symmetrical variations of potential in a train-carried grid-filament circuit, a train,

a train-carried electron tube having a plate, a grid and a filament, the potential of the grid being controlled jointly by two factors including the following means: (1) altraincarried grid-filament circuit continuously re-' a sponsive to the influence of the current in the "rails to thereby continuously reflect trafiicconditions thereof and. (2) a power source connected to the grid-filament circuit, said power source constantly tending to establish "a predetermined potential of the grid notwithstanding changes in traflic conditions; a

a charged train-carried plate-filament circuit,

the average value of thecurrent flowingin v when variations of potential are absent from I i the grid-filament circuit.

15.1.&continuously acting train control system including: a traflic track composed of rails arranged in blocks, a train, a traincarried electron tube detector having a plate, a grid and a'filament, a plate-filament cir e cuit, acurrent source that charges saidfcir cuit with current ofagiven average value,

direct-current relay means responsive to the influence of a change n the average value of current flowlng 1n the plate-filament-circult, I

a grid-filament circuit responsive to the influence of current flowing in the rails of the traffic track, a power source connected tof the grid-filament circuit tending at all times to establish ,a certain "potential on the grid with respect tothe filament, and a trackway current source to supply, under proceed traflic conditions, currentof varying poten-, tial to therails to thereby exert an influence cuit, symmetrical variations in thegrid-filament circuit producing asymmetrical variations in the current of the plate-filament circuit to therebyv varythe average value of current flowing in said;

plate-filament circuit.

' 16. A train. control system including a traific track arranged in blocks, a train, a

train-carried electron tube havinga plate,

cuit, a'currentsource that charges said cirdirect-current relay means responsive to'the a filament and a grid, a plate-filament;cir.-',;

,i cuit with current of a given average value,

influence of a change in the average'value of current flow in the plate-filament circuit, and

' means-to .vary the. average value of current flow in the plate-filament circuit sym metrical variation-s in-the potential of the grid with respect to the filament including:

a traffic-controlled 'trackway source of 1' power and a train-carried source of power ointly non-responsive totraflic conditions to influence. thepotential of the grid. i

13th day of'June, 1929.

said plate-filament circuit being determined 1 3 by the joint control of said two factors, a direct-current polarized relay responsive to a change in the average valueof the current,

flowing in the plate-filament circuit, and an armature having a pendulous movement" associated (with said polarized relaythat 5 i swings inone direction whenxthe grid po-' tential the result of the action'of both 5 factors and thatswings in the other direction Signed. at Pittsburgh,- in the county of Allegheny and State of Pennsylvania, this I I a 115.. G. WILLIAMSON. 1 

